use python in docker

Dockerfile

@@ -1,8 +1,8 @@
 # Container image that runs your code
-FROM alpine:3.10
+FROM python:3.7-slim-buster
 
 # Copies your code file from your action repository to the filesystem path `/` of the container
-COPY checkwebsite.sh /checkwebsite.sh
+COPY deadseeker.py /deadseeker.py
 
-# Code file to execute when the docker container starts up (`checkwebsite.sh`)
-ENTRYPOINT ["/checkwebsite.sh"]
+# Code file to execute when the docker container starts up (`deadseeker.py`)
+CMD [ "python", "deadseeker.py" ]

deadseeker.py

@@ -0,0 +1,73 @@
+'''
+deadseeker.py
+Seeking out your 404s in around 50 lines of vanilla Python.
+'''
+
+import sys
+import urllib
+from urllib import request, parse
+from urllib.parse import urlparse, urljoin
+from urllib.request import Request
+from html.parser import HTMLParser
+from collections import deque
+
+search_attrs = set(['href', 'src'])
+excluded_link_prefixes = set(['mailto:'])
+agent = 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/60.0.3112.113 Safari/537.36'
+
+
+class LinkParser(HTMLParser):
+    def __init__(self, home, verbose):
+        ''':home:    a homepage, e.g. 'https://healeycodes.com/'
+           :verbose: boolean for for verbose mode'''
+        super().__init__()
+        self.home = home
+        self.verbose = verbose
+        self.checked_links = set()
+        self.pages_to_check = deque()
+        self.pages_to_check.appendleft(home)
+        self.scanner()
+
+    def scanner(self):
+        '''Loop through remaining pages, looking for HTML responses'''
+        while self.pages_to_check:
+            page = self.pages_to_check.pop()
+            req = Request(page, headers={'User-Agent': agent})
+            res = request.urlopen(req)
+            if 'html' in res.headers['content-type']:
+                with res as f:
+                    body = f.read().decode('utf-8', errors='ignore')
+                    self.feed(body)
+
+    def handle_starttag(self, tag, attrs):
+        '''Override parent method and check tag for our attributes'''
+        for attr in attrs:
+            # ('href', 'http://google.com')
+            if attr[0] in search_attrs and attr[1] not in self.checked_links and not attr[1].startswith(tuple(excluded_link_prefixes)):
+                self.checked_links.add(attr[1])
+                self.handle_link(attr[1])
+
+    def handle_link(self, link):
+        '''Send a HEAD request to the link, catch any pesky errors'''
+        if not bool(urlparse(link).netloc):  # relative link?
+            link = urljoin(self.home, link)
+        try:
+            req = Request(link, headers={'User-Agent': agent}, method='HEAD')
+            status = request.urlopen(req).getcode()
+        except urllib.error.HTTPError as e:
+            print(f'HTTPError: {e.code} - {link}')  # (e.g. 404, 501, etc)
+        except urllib.error.URLError as e:
+            print(f'URLError: {e.reason} - {link}')  # (e.g. conn. refused)
+        except ValueError as e:
+            print(f'ValueError {e} - {link}')  # (e.g. missing protocol http)
+        else:
+            if self.verbose:
+                print(f'{status} - {link}')
+        if self.home in link:
+            self.pages_to_check.appendleft(link)
+
+
+# check for verbose tag
+verbose = len(sys.argv) > 2 and sys.argv[2] == 'v'
+# enable this as a script, e.g., 'https://healeycodes.com/ v'
+LinkParser(sys.argv[1], verbose)